Belted pneumatic tires with zero degree breaker reinforcement, and method of building such tires

ABSTRACT

A breaker reinforcing tape for belted pneumatic tires, a method of making such tape, and a method of constructing such tires therewith, are disclosed. The tape includes a generally sinusoidally crimped strip of uncured rubber and a plurality of similarly crimped parallel cords having their undulations following and nesting in the undulations of the crimped strip, the cords at successive apexes being secured to successive apexes of the strip. A second uncured rubber strip in a flat condition is secured to alternate ones of the apexes of the undulations of the array of cords and the crimped strip at one face of the latter. At least one frangible element is interposed in a fixed and substantially flat condition between the crimped and flat strips for releasably reinforcing and stabilizing the flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of the crimped strip and its associated cords. The tape, when used in making a tire, is wound helically about the crown region of the carcass, outwardly of the breaker plies, at an angle of substantially zero degrees to the mid circumferential plane of the carcass. This abstract is not to be taken either as a complete exposition or as a limitation of the present invention, however, the full nature and extent of the invention being discernible only by reference to and from the entire disclosure.

BACKGROUND OF THE INVENTION

The present invention relates generally to pneumatic tire carcasses, andmore particularly to a breaker-functioning tape for reinforcing a radialply tire carcass capable of being constructed in a single stage; namely,in one stage, on a single drum, in which a breaker assembly and a treadare applied to the carcass plies before the unit is converted from asubstantially cylindrical condition to a substantially toroidalcondition.

Radial ply tire manufacturers in increasing numbers are now attemptingto build radial ply tires in a single stage to eliminate the need forthe additional "second stage" equipment and labor typically required forsuch tire construction. In this regard, conventional procedure forconstructing radial ply tires includes a "first stage" in which thecarcass or body plies are wound on a substantially cylindrical buildingdrum. Thereafter, among other things, beads are applied and anchored tothe opposite end portions of the cylindrically arranged body plies, andthe entire unit (or "first stage carcass") is transformed into acylindrical form. The cylindrical "first stage carcass" is thentransferred to conventional "second stage" equipment at which thecylindrical form is shaped to a toroidal shape and where breaker pliesand tread are applied to it for transformation into a "second stagecarcass" ready for vulcanization. The additional equipment and labornecessary for effecting the "second stage" as an independent operationis excessively costly not only with respect to equipment and labor, butalso with respect to time and space necessary for storing the additionalequipment. Clearly, the conventional "two stage" radial ply tireconstructing operations are not entirely desirable.

In order to eliminate the "second stage", radial ply tire manufacturershave been applying the breaker plies and tread to the radial ply carcassor body plies in much the same way and on equipment much the same as forbuilding conventional bias ply tires; namely, before the cylindricalcarcass is transformed into a toroid. However, such manufacturers haeencountered the difficulty of using breaker plies whose substantiallyinextensible cords from a high bias angle (in excess of 35°) with amedian equatorial plane of the carcass, and thus readily pantograph toaccommodate the substantial expansion of the carcass into a toroid. Ahigh bias angle provides for a satisfactory lateral stiffness in thebreaker plies, but at the cost of an unsatisfactory or insufficientamount of circumferential stiffness. An insufficient amount ofcircumferential stiffness will result in an unacceptably high rate oftread wear.

It has been proposed, for example, in conjunction with the disclosure inU.S. Pat. No. 3,900,062, issued on Aug. 19, 1975, the subject matter ofwhich is hereby incorporated by reference herein, to wind in helicalfashion a knitted tape, capable of undergoing only a prescribed limitedamount of expansion, around the breaker plies to reinforce or supplementthe latter with the necessary amount of circumferential stiffness. Theknitted tape is provided with a plurality of side by side, substantiallyinextensible, rubbered encapsulated, cords that are crimped withsinusoidal undulations and releasably held as a unit adjacent to oneanother by, for example, a frangible cord knitted into and through theundulations.

One difficulty associated with the use of such a breaker-functioningknitted tape is its relatively high expense to fabricate. Theinextensible cords are encapsulated in a sheath of rubber by anextrusion process that is excessively costly, and then knitted to oneanother, compounding the cost.

Another difficulty associated with the use of any breaker-functioningtape is the manner by which it is only helically wound, near zerodegrees, around the underlying carcass construction. A tire completed insuch a manner sometimes displays uneven tread wear in much the same waythat would be displayed by the tread of a tire on a vehicle requiring anadjustment in alignment. It is theorized that the helical tape turns actsomething akin to screw threads forcing the tire components to shift ortwist slightly relative to one another as the tire turns. This causescertain portions of the tread at the "footprint" or tread/road interfaceto shimmy or pivotally skid about an imaginary vertical axis normal tothe footprint, thereby effecting concentrated high local stress andtread abrasion.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention toprovide a new and improved breaker reinforcing tape for constructingsingle stage, radial ply tires that does not have associated therewiththe aforementioned disadvantages.

More particularly, it is an object of the present invention to provide abreaker reinforcing tape that is simplified and less costly than suchtapes heretofore known.

It is a further object of the present invention to provide a new methodby which a breaker reinforcing tape should preferably be wound around abreaker assembly so as to prevent uneven tread wear.

With the above and additional objects in view, the present inventionwith respect to the breaker reinforcing tape comprises a crimped striphaving continuous sinusoidal undulations, a plurality of cords extendingside by side in parallel relation longitudinally along the strip, eachof the cords having respective undulations corresponding to and nestingin the undulations of the strip, means for anchoring the apexes of theundulations of each of the cords to corresponding ones of the apexes ofthe undulations of the strip, a flat strip having a width substantiallycorresponding to the width of the crimped strip, means for anchoring theflat strip to alternate ones of the apexes of the undulations of thecrimped strip, and frangible means interposed between the flat andcrimped strips for releasably reinforcing and stabilizing the integrityof the flat strip against inadvertent expansion that would prematurelyreduce the amplitude and frequency (number of undulations per unitlength) of the undulations of the crimped strip and cords.

With respect to the method of the present invention, a carcass isconstructed from at least one body ply and at least one breaker plywound in succession around a carcass building drum. Thereafter, the tapeof the present invention is wound helically around the breaker plybetween the opposite edges thereof at substantially zero degreesrelative to a median equatorial plane of the plies, the tape windingsinitiating and terminating in a respective end turn that extendscircularly and non-helically over a full 360° around the breaker ply andoverlaps itself at least partially. The carcass construction iscontinued by winding a tread-and-sidewall slab around the tape and thebreaker and body plies, the slab at least in the tread region thereofhaving perforations to enable air entrapped therebeneath in the tape tobe evacuated after beads are applied and anchored and the entireassembly is inflated into a torus.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more clearly understood from the followingdetailed description thereof when read in conjunction with theaccompanying drawings, in which:

FIG. 1 is an enlarged, fragmentary, perspective view of the tape of thepresent invention;

FIG. 2 is a further enlarged, fragmentary, perspective view of the tapeof the present invention from which there is absent, for purposes ofillustration, the crimped strip;

FIG. 3 is a side elevational view of the tape structure illustrated inFIG. 1;

FIG. 4 is a cross-sectional view taken along the line 4--4 in FIG. 1;

FIG. 5 is a cross-sectional view taken along the line 5--5 in FIG. 1;

FIG. 6 is a fragmentary, cross-sectional view of the pneumatic tirecarcass construction of the present invention on a carcass buildingdrum;

FIG. 7 is a schematic, fragmentary view of the carcass of the presentinvention before application thereto of the tape; and

FIG. 8 is a schematic view illustrating the full 360° initiating andterminating end turns of the tape of the present invention as it wouldbe wound on a tire carcass pursuant to the method of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, and more particularly to FIGS. 1 through5, the present invention involves a tape denoted generally by thereference character 20. The tape 20 includes an uncured, elastomeric,crimped strip 22 and an uncured elastomeric, flat strip 24. The strips22 and 24 may be constituted of natural and/or synthetic rubbers orrubber mixtures that can be stretched and compressed, and are compatiblewith building pneumatic tires. Preferably, such strips 22 and 24 arealso tacky for adhering to various components used in the constructionof pneumatic tires, and particularly radial ply tires.

Between the strips 22 and 24, there is interposed a plurality of crimpedcords 26 extending side by side in parallel relation longitudinallyalong the strips. The cords 26 are substantially inextensible, and haverespective, for example, sinusoidal, undulations that with regard to thecord with which they correspond are substantially coplanar, and withregard to adjacent cords are laterally aligned or "in phase" with oneanother. The cords may be of the type of material known as Kevlar orKevlar Aramid and sold by the Dupont Company. As best illustrated inFIG. 3, alternate ones of the apexes 28 of the undulations of each ofthe cords 26 are secured to the crimped strip 22, whereas the otheralternate ones of the apexes 30 are secured to and tightly between thecrimped strip 22 and the flat strip 24.

In this regard, the strips 22 and 24 are each compressible and tacky. Assuch, the cords 26 can be impressed into the surfaces of the strips 22and 24 by any convenient means, and will remain so affixed thereto.Particularly, it is the apexes 28 and 30 of the undulations of each ofthe cords 26 that are first impressed into the strip 22. Thereafter, theflat strip 24 is pressed against the assembly of the crimped strip 22and cords 26 only at the apexes 30 of the cords 26 and the correspondingregions of the strip 22. It is, thus, the flat strip 24 that sustainsthe crimped strip 22 and cords 26 in an undulation-presenting condition.It is the tacky condition of the strips 22 and 24 and their readycompressibility and impressibility that secures the assembly as a unit.

In order to assure the integrity of the flat strip 24 againstinadvertent expansion that would prematurely reduce the amplitude andfrequency (number of undulations per unit length of the strip 22) of theundulations of the crimped strip 22, and particularly assure that thetape 20 is provided with a reliable length that under prescribed tensilepressure is substantially invariable, frangible means in the form, forexample, of one or more thin cotton elements 32 are fixedly predisposedin parallel relation flat along the flat strip 24 as the strip 24 isapplied to the assembly of the crimped strip 22 and cords 26. The cottonelements 32 have a cross-sectional size that is less than thecross-sectional size of each of the cords 26 and may, for example, tearonly after being subjected to tensile load in excess of five pounds.Needless to say, the tensile strength of the elements 32 must be greaterthan the stretch-resistance of the strip 24.

With respect to the cords 26, it is preferred that they be provided withweakened regions such as nicks or the like to enable the cords torupture selectively at prescribed tensile loads. It is also preferredthat such nicks or weakened regions in the cords 26 be staggeredrelative to one another from cord to cord so that should more than oneof the cords rupture, they will not do so along the same lateral line ofthe tape 20. The depth of the nicks, for example, is selected to reducethe full tensile strength of each of the cords 26 to between about fivepercent and twenty percent of its original tensile strength.

Pursuant to the illustrated embodiment of the tape 20, it is comprisedof nine cords 26 and has a width of, for example, 5/8 inches. It will beunderstood, however, that other numbers of such cords 26 may beselected, as well as other tape widths, depending on the particularpurpose the tape 20 is to serve, and the particular pneumatic tirecomponents and sizes it is to be constructively arranged with.

It is contemplated, pursuant to the present invention, that the tape 20be utilized as an outer breaker for belted, radial ply tires capable ofbeing constructed in a single stage. In this regard, it is contemplatedthat the tape 20 may be helically wound around a raw or uncured tirecarcass such as that illustrated in FIG. 6 and denoted generally by thereference character 40. The carcass 40 is comprised of a pair of bodyplies 42 and 42a each reinforced with, for example, polyester cords 43(FIG. 7), and a pair of breaker plies or belts 44 and 44a eachreinforced with, for example, glass cords 45 (FIG. 7). The body plies,42, 42a are arranged cylindrically on a carcass building drum 46 suchthat the parallel polyester cords 43 thereof run parallel to the axis ofthe drum or at 90° relative to a median equatorial plane of the carcass.The breaker plies 44, 44a, on the other hand, are arranged cylindricallyaround the body plies 42, 42a such that their respective glass cords 45from belt to belt run oppositely of one another, and within each beltrun parallel to one another at an angle relative to the medianequatorial plane of the carcass in excess of 35° and preferablyapproximately 45°.

The cylindrical carcass 40 of the body plies 42, 42a and breaker plies44, 44a is to be reinforced by the tape 20 by winding the latterhelically around the outer breaker ply 44 from one edge thereof to theother. However, pursuant to a principal concept of the presentinvention, the tape 20 is wound around the breaker ply 44 in a preferredmanner. In this regard, as best illustrated in FIG. 8, the very firstturn 50 of the tape 20 is wound around the outer breaker ply 44 near oradjacent to one edge thereof entirely at zero degrees, or, moreparticularly, circularly and non-helically such that it extends a full360° and then overlaps itself at least in part without straying from itszero degree pitch. Once such a partial overlap is achieved, the pitch ofthe tape turn locus can be altered from zero degrees into a helical pathnear, but slightly in excess of, zero degrees until the entire breakerply 44 is helically covered. The last turn, however, is terminated inthe same manner as the first turn is initiated. As such, the last turn52 is effected entirely at zero degrees, circularly and non-helically,such that it extends a full 360° and then overlaps itself at least inpart at the opposite edge of the breaker ply 44.

After the tape 20 is applied to the carcass 40, a pair of beads isapplied and anchored to the opposite end portions of the assembly, atread-and-sidewall slab 54, perforated at least between the oppositeedges of the breaker ply 44, for example, at 55, is wound upon theassembly, and the cylindrical assembly is transformed into the shape ofa torus in the curing press. As the assembly is so transformed, theglass cords 45 of the breaker plies 44, 44a pantograph slightly toaccommodate the circumferential expansion of such plies, and the tape 20is stretched taut. As the tape 20 is so stretched, the undulations ofits cords 26 and of the strip 22 are completely flattened, and thefrangible cotton elements are torn. Moreover, air entrapped in thecrimped undulations of the tape 20 beneath the tread-and-sidewall slab54 is forcibly discharged through the venting perforations 55 of theslab 54 during such circumferential expansion of the carcass components.

It will be understood that the amplitude and frequency of theundulations of the tape 20 is selected as a function of the elongationthat the tape will undergo as the cords are transformed from theirinitial crimped condition on the cylindrical carcass 40 to their finalstraightened condition on the toroidal carcass. The amount of permitted"soft stretch" or substantially non-stressed elongation of the tape thusis the difference between the crimped cord length and the straight cordlength. It is preferred, in this regard, that the inextensible cords 26should not be physically stretched. However, since the cords are nickedperiodically, should they become overstressed somewhat during thecircumferential expansion of the carcass 40, such nicks will tear orstretch slightly to allow for final crown curvature or even forprocessing variations, or to prevent cords 26 from being pulleddamagingly into abrasive engagement with the underlying glass cords 45of the outer breaker ply 44.

The cylindrical belted, radial carcass 40, when ready for vulcanizationinto its final tire product condition, thus is a "single stage"intermediate article requiring no additional steps of construction. Inthe finished tire, the full 360° initiating and terminating end turns ofthe tape 20 prevent the intermediary helical turns thereof from causingtwisting of the tire components relative to one another at thetread/road interface and thereby prevent excessive, uneven tread wear.Such end turns, therefore, stabilize the tire and prolong its usefullife.

It will be understood that the foregoing description of the preferredembodiments of the present invention is for purposes of illustrationonly, and that the various structural and operational features andrelationships herein disclosed are susceptible to a number ofmodifications and changes none of which entails any departure from thespirit and scope of the present invention as defined in the heretoappended claims. Merely by way of example, if it is desired to build azero degree belted tire having no bias-angled breaker plies around thecrown region of the carcass, the zero degree belt-forming structure canbe attained by winding the tape, at the 0° winding angle and in themanner herein described, directly onto the body plies of the tirecarcass.

What is claimed is:
 1. An uncured belted pneumatic tire, comprising a carcass composed of at least one body ply, and a belt-forming structure surrounding said body ply in the medial region of said carcass, said belt-forming structure being constituted by a tape of cords wound substantially helically around said medial region of said carcass with a multiplicity of turns having a pitch of substantially zero degrees relative to the median equatorial or mid-circumferential plane of said carcass, said tape initiating and terminating in a respective end turn that extends circularly and non-helically over a full 360° around said body ply and overlaps itself at least partially, and said tape comprising a crimped strip having continuous undulations, a plurality of said cords extending side by side in parallel relation longitudinally along said crimped strip, each of said cords having respective undulations corresponding to and nesting in the undulations of said crimped strip, first means for anchoring the apexes of the undulations of each of said cords to corresponding ones of the apexes of the undulations of said crimped strip, a flat strip having a width substantially corresponding to the width of said crimped strip, second means for anchoring said flat strip to alternate ones of the apexes of the undulations of said crimped strip, and frangible means interposed between said flat and crimped strips for releasably reinforcing and stabilizing said flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of said crimped strip and of said cords.
 2. An uncured tire as claimed in claim 1, wherein said crimped and flat strips are elastomeric and tacky.
 3. An uncured tire as claimed in claim 2, wherein said first anchoring means is constituted by respective portions of said cords engaging and impressed into corresponding portions of said crimped strip.
 4. An uncured tire as claimed in claim 3, wherein said second anchoring means is constituted by respective portions of said flat and crimped strips mutually engaging and pressed into one another.
 5. An uncured tire as claimed in claim 1, wherein said cords are flexible but substantially inextensible.
 6. An uncured tire as claimed in claim 5, wherein said cords are constituted of aramid fiber.
 7. An uncured tire as claimed in claim 5, wherein said frangible means includes at least one flexible filament having a tensile strength that is greater than the stretch resistance of at least said flat strip.
 8. An uncured tire as claimed in claim 7, wherein said tensile strength of said flexible filament is such that the latter will tear when subjected to a load of approximately 5 pounds.
 9. An uncured tire as claimed in claim 7, wherein said flexible filament is fixedly predisposed between said flat and crimped strips in a substantially straight condition.
 10. An uncured tire as claimed in claim 7, wherein said flexible filament is constituted of cotton and has a cross-sectional size that is less than the cross-sectional size of each of said cords.
 11. An uncured tire as claimed in claim 5, wherein said cords are each provided with at least one nick, and said nicks in adjacent ones of said cords are staggered relative to one another.
 12. An uncured tire as claimed in claim 1, wherein said crimped and flat strips of said tape have a width each of approximately 5/8 inch.
 13. An uncured belted pneumatic tire, comprising a carcass composed of at least one substantially cylindrical body ply, at least one breaker ply surrounding and secured to said body ply in the medial region of said carcass, and a breaker reinforcement-forming cord structure surrounding said breaker ply, said structure being in the form of a tape wound substantially helically around said breaker ply at an angle of substantially zero degrees to the mid-circumferential plane of said carcass, said tape initiating and terminating in a respective end turn that extends circularly and non-helically over a full 360° around said body ply and overlaps itself at least partially, and said tape comprising a crimped strip having continuous undulations, a plurality of cords extending side by side in parallel relation longitudinally along said crimped strip, each of said cords having respective undulations corresponding to and nesting in the undulations of said crimped strip, first means for anchoring the apexes of the undulations of each of said cords to corresponding ones of the apexes of the undulations of said crimped strip, a flat strip having a width substantially corresponding to the width of said crimped strip, second means for anchoring said flat strip to alternate ones of the apexes of the undulations of said crimped strip, and frangible means interposed between said flat and crimped strips for releasably reinforcing and stabilizing said flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of said crimped strip and of said cords.
 14. An uncured tire as claimed in claim 13, wherein said tape is wound with said end turns thereof disposed intermediate the opposite edges of said breaker ply.
 15. An uncured tire as claimed in claim 13, wherein said carcass comprises a second said body ply and a second breaker ply, each of said body and breaker plies having encapsulated therein a respective plurality of spaced, parallel reinforcing cords, the reinforcing cords of said body plies extending at substantially 90° relative to said mid-circumferential plane of said carcass, the reinforcing cords of said breaker plies being oppositely oriented from ply to ply relative to said mid-circumferential plane and forming an angle relative thereto which in each breaker ply is in excess of approximately 35°.
 16. An uncured tire as claimed in claim 13, wherein the reinforcing cords of said body ply are constituted of polyester, and the reinforcing cords of said breaker ply are constituted of glass.
 17. An uncured tire as claimed in claim 13, further comprising a tread slab affixed to said carcass in surrounding relation to said structure, said tread slab having perforations at least between said 360° opposite end turns of said tape.
 18. An uncured tire as claimed in claim 13, wherein said crimped and flat strips are elastomeric and tacky.
 19. An uncured tire as claimed in claim 18, wherein said first anchoring means is constituted by respective portions of said cords engaging and impressed into corresponding portions of said crimped strip.
 20. An uncured tire as claimed in claim 19, wherein said second anchoring means is constituted by respective portions of said flat and crimped strips mutually engaging and pressed into one another.
 21. An uncured tire as claimed in claim 13, wherein said cords are flexible but substantially inextensible.
 22. An uncured tire as claimed in claim 21, wherein said cords are constituted of aramid fiber.
 23. An uncured tire as claimed in claim 21, wherein said frangible means includes at least one flexible filament having a tensile strength that is greater than the stretch resistance of at least said flat strip.
 24. An uncured tire as claimed in claim 23, wherein said tensile strength of said flexible filament is such that the latter will tear when subjected to a load of approximately five pounds.
 25. An uncured tire as claimed in claim 23, wherein said flexible filament is fixedly predisposed between said flat and crimped strips in a substantially straight condition.
 26. An uncured tire as claimed in claim 23, wherein said flexible filament is constituted of cotton and has a cross-sectional size that is less than the cross-sectional size of each of said cords.
 27. An uncured tire as claimed in claim 13, wherein said cords are each provided with at least one nick, and said nicks in adjacent ones of said cords are staggered relative to one another.
 28. An uncured tire as claimed in claim 13, wherein said crimped and flat strips of said tape have a width each of approximately 5/8 inch.
 29. An uncured belted pneumatic tire, comprising a carcass composed of at least one body ply, and a belt-forming structure surrounding said body ply in the medial region of said carcass, said belt-forming structure being constituted by a tape of cords wound substantially helically around said medial region of said carcass with a multiplicity of turns having a pitch of substantially zero degrees relative to the median equatorial or mid-circumferential plane of said carcass, said tape initiating and terminating in a respective end turn that extends circularly and non-helically over a full 360° around said body ply and overlaps itself at least partially, and said tape comprising a crimped strip having continuous undulations, a plurality of said cords extending side by side in parallel relation longitudinally along said crimped strip, each of said cords having respective undulations corresponding to and nesting in the undulations of said crimped strip, first means for anchoring each of said cords to said crimped strip, a flat strip having a width substantially corresponding to the width of said crimped strip, second means for anchoring said flat strip to alternate ones of the apexes of the undulations of said crimped strip, and frangible means coextensive with said flat strip for releasably reinforcing and stabilizing said flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of said crimped strip and of said cords.
 30. An uncured tire as claimed in claim 29, wherein said first anchoring means is constituted by respective portions of said cords at the apexes of the undulations thereof engaging and impressed into corresponding juxtaposed portions of said crimped strip at the apexes of its undulations.
 31. An uncured tire as claimed in claim 29, wherein said second anchoring means is constituted by the respective alternate ones of said apexes of the undulations of said crimped strip and the juxtaposed portions of said flat strip mutually engaging and pressed into one another.
 32. An uncured tire as claimed in claim 29, wherein said frangible means is interposed between said flat and crimped strips and includes at least one flexible filament having a tensile strength that is greater than the stretch resistance of at least said flat strip.
 33. An uncured belted pneumatic tire, comprising a carcass composed of at least one substantially cylindrical body ply, at least one breaker ply surrounding and secured to said body ply in the medial region of said carcass, and a breaker reinforcement-forming cord structure surrounding said breaker ply, said structure being in the form of a tape wound substantially helically around said breaker ply at an angle of substantially zero degrees to the mid-circumferential plane of said carcass, said tape initiating and terminating in a respective end turn that extends circularly and non-helically over a full 360° around said body ply and overlaps itself at least partially, and said tape comprising a crimped strip having continuous undulations, a plurality of cords extending side by side in parallel relation longitudinally along said crimped strip, each of said cords having respective undulations corresponding to and nesting in the undulations of said crimped strip, first means for anchoring each of said cords to said crimped strip, a flat strip having a width substantially corresponding to the width of said crimped strip, second means for anchoring said flat strip to alternate ones of the apexes of the undulations of said crimped strip, and frangible means coextensive with said flat strip for releasably reinforcing and stabilizing said flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of said crimped strip and of said cords.
 34. An uncured tire as claimed in claim 33, wherein said first anchoring means is constituted by respective portions of said cords at the apexes of the undulations thereof engaging and impressed into corresponding juxtaposed portions of said crimped strip at the apexes of its undulations.
 35. An uncured tire as claimed in claim 33, wherein said second anchoring means is constituted by the respective alternate ones of said apexes of the undulations of said crimped strip and the juxtaposed portions of said flat strip mutually engaging and pressed into one another.
 36. An uncured tire as claimed in claim 33, wherein said frangible means is interposed between said flat and crimped strips and includes at least one flexible filament having a tensile strength that is greater than the stretch resistance of at least said flat strip.
 37. A method of constructing a raw belted pneumatic tire, comprising the steps of wrapping at least one body ply around a tire building drum, and winding a multiplicity of turns of a breaker-forming tape helically around a medial portion of said body ply between the opposite edges thereof at substantially zero degrees relative to the mid-circumferential plane of said body ply, said winding of said breaker-forming tape initiating and terminating in a respective end turn that extends circularly and non-helically over a full 360° around said body ply and overlaps itself at least partially, and said tape comprising a crimped strip having continuous undulations, a plurality of cords extending side by side in parallel relation longitudinally along said crimped strip, each of said cords having respective undulations corresponding to and nesting in the undulations of said crimped strip, first means for anchoring the apexes of the undulations of each of said cords to corresponding ones of the apexes of the undulations of said crimped strip, a flat strip having a width substantially corresponding to the width of said crimped strip, second means for anchoring said flat strip to alternate ones of the apexes of the undulations of said crimped strip, and frangible means interposed between said flat and crimped strips for releasably reinforcing and stabilizing said flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of said crimped strip and of said cords.
 38. A method as claimed in claim 37, and comprising the further step, to precede the winding of said tape around said body ply, of wrapping at least one breaker ply of reduced axial extent around said body ply, said tape winding step being performed to dispose said tape directly around said breaker ply.
 39. A method as claimed in claim 38, said tape winding step being performed to dispose said full 360° circular and non-helical initiating and terminating end turns of said tape intermediate the opposite edges of said breaker ply.
 40. A method of constructing a raw belted pneumatic tire, comprising the steps of wrapping at least one body ply around a tire building drum, and winding a multiplicity of turns of a breaker-forming tape helically around a medial portion of said body ply between the opposite edges thereof at substantially zero degrees relative to the mid-circumferential plane of said body ply, said winding of said breaker-forming tape initiating and terminating in a respective end turn that extends circularly and non-helically over a full 360° around said body ply and overlaps itself at least partially, and said tape comprising a crimped strip having continuous undulations, a plurality of cords extending side by side in parallel relation longitudinally along said crimped strip, each of said cords having respective undulations corresponding to and nesting in the undulations of said crimped strip, first means for anchoring each of said cords to said crimped strip, a flat strip having a width substantially corresponding to the width of said crimped strip, second means for anchoring said flat strip to alternate ones of the apexes of the undulations of said crimped strip, and frangible means coextensive with said flat strip for releasably reinforcing and stabilizing said flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of said crimped strip and of said cords.
 41. A method as claimed in claim 40, wherein said first anchoring means is constituted by respective portions of said cords at the apexes of the undulations thereof engaging and impressed into corresponding juxtaposed portions of said crimped strip at the apexes of its undulations.
 42. A method as claimed in claim 40, wherein said second anchoring means is constituted by the respective alternate ones of said apexes of the undulations of said crimped strip and the juxtaposed portions of said flat strip mutually engaging and pressed into one another.
 43. A method as claimed in claim 40, wherein said frangible means is interposed between said flat and crimped strips and includes at least one flexible filament having a tensile strength that is greater than the stretch resistance of at least said flat strip. 